This invention relates generally to an improved pneumatic radial drive tire for agricultural use under dry, wet or moist soil conditions requiring a tire with high flotation and deep tread characteristics. The improved tire more specifically relates to a new agricultural tire particularly well suited for cotton, rice, and cane farm tire applications.
The treads of agricultural tires have a plurality of ground or soil penetrating lugs. The lugs dig into the soil and provide the traction forces necessary to move the vehicle. The tread has an inner tread surface that generally rides on top of the soil and provides the flotation necessary to keep the tire from sinking too deeply into the soil.
Generally the agricultural tire works well on loose but relatively stable soil. In such applications a lug of the type known in the industry as R1 performs quite well.
It has been recognized that the R1 type tire is generally not well suited for wet sloppy soil conditions as are con, hotly found in rice or cane fields. A lug of the configuration known in the art as R2 was developed for such applications.
The R2 type lug is a very deep soil penetrating lug. The R2 lug acts like a paddle penetrating the muck and shoving it through channels axially and circumferentially outwardly thus providing mobility in otherwise impassible or untillable soil.
The use of R2 type tires is con, non on lands with tracts of low lying moist bottom land. Such tracts of land can range in soil conditions from hard and firm to wet and sloppy. A desirable feature of a well designed R2 type tire is that it works well under the full range of soil conditions.
A second consideration in modern agricultural activities is that the tire must be driveable on paved roadways. Tractors, combines, or cotton pickers till or work vast amounts of land in a relatively short period of time. Farmers invest in powerful and expensive equipment that must be highly utilized to efficiently recover the capital investment outlaid. A typical farmer my farm tracts of land several miles apart. The equipment must either be trucked to the other locations or driven there.
Farmers prefer to be able to drive the equipment directly to other fields. It is considered faster and easier to simply pull out of a field onto a road and drive directly to the next field.
Deep lug tractor tires however are designed primarily for loose soil conditions. The weight of large equipment running at speeds of 25 mph on hard paved surfaces generates high heat build up in the tires which causes premature lug wear. The problem is particularly acute with the conventional deep lug R2 rice and cain tires.
Extended roadway travel under the heavy load of large combines, tractors, and pickers has been known to build up so much heat that the lugs often tear and completely fold over. The large deep paddle like lugs of the R2 type tire are particularly prone to such problems.
Attempts to make the R2 type tire more road worthy have been directed to strengthening the lug by increasing the bracing, enlarging the lug head, thickening the lug width or by providing center ribs projecting from the inner tread at the equatorial plane of the tire. Such solutions invariably result in a loss of tire performance in the field. Pulling traction and the ability to traverse the wet moist soil are reduced.
A tire made in accordance with the present invention has provided a rice cane type tire with a modified R2 type lug that is roadworthy without appreciable loss of field performance.